Paired roller configuration

ABSTRACT

A paired roller configuration is described and contains a first roller disposed rotatably in a first machine unit and a second roller disposed rotatably in a second machine unit and substantially parallel to the first roller. The first and second rollers guide a web that wraps partly around the first and second rollers. The first roller is disposed such that it can move in the first machine unit and, by at least one connecting unit, is connected to the second roller in such a way that in the event of movement and/or deformation of the first machine unit, the first roller and the second roller remain disposed substantially parallel to each other and at a substantially constant spacing.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The invention relates to a paired roller configuration that contains a first roller disposed rotatably in a first machine unit and a second roller disposed rotatably in a second machine unit and substantially parallel to the first roller. The first and second rollers guide a web that wraps partly around the first and the second rollers.

[0002] The prior art discloses web-processing machines, for example web-fed rotary printing machines, in which a web is guided through a plurality of machine units in the web-processing machine and, in the process, is subjected to different processing processes, for example printing, drying, cooling or folding. In the process, the web to be processed, which may be a paper web, a textile or plastic web, for example, is guided over guide units, such as rotating rollers or non-rotating guide rods or turner rods, it also being possible for the direction to be changed or for the web to be turned.

[0003] German Patent DE 31 28 430 C2 discloses a rotary printing machine having a cooling mechanism which follows a drier and which is composed of a plurality of machine units disposed one after another in the web running direction. In this case, the web passes successively through a reel changer, a tension regulator, a plurality of printing units, a web catching device, a drier, a cooling roller stand and a folder. The individual machine units in the rotary printing machine, in particular the drier and the cooling roller stand are in this case disposed spaced apart from one another, and the web is moved onward from a first machine unit to a second machine unit without any interposed web guide elements. In such rotary printing machines, there is in principle the necessity to keep the tension of the web within a permanently predefined value range, so that optimal printing and folding results can be produced and, in particular, a web break can be avoided. Disadvantageous changes in the web tension can arise in such a web-fed rotary printing machine for example because a machine unit in the web-fed rotary printing machine, in which the web is led over web guide elements, expands or deforms on account of temperature fluctuations. This consequently leads to a disadvantageous movement of the machine unit together with the web guide elements, so that the distance between the individual machine units, and therefore also the length of the web path, varies, which brings about a change in the web tension, at least in the web section between the two machine units. Furthermore, deformation of the machine unit leads to a non-uniform distribution of the web tension over the width of the web, so that creasing, in particular longitudinal and diagonal creases, and web offset occur in the web section.

[0004] European Patent EP 0 627 311 B1 shows a web cooling device which, in the web running direction, is disposed directly downstream of a hot-air drier, in such a way that the housing of the web cooling device directly adjoins the housing of the drier. Furthermore, the prior art discloses the fact that hot air driers have a combustion chamber to heat the gas in the drier and, during operation, produce temperatures of the order of magnitude of 200 to 300° C. in the drier. As a result of the temperature prevailing in the drier, apart from the intended heating of the web, the drier housing is also heated, which, as a result, can expand by several centimeters in the case of a drier length of about 10 to 15 m. The expansion of the housing consequently leads to a movement or, in the event of non-uniform heat distribution in the drier, to deformation of the drier, the movement being transmitted to the web cooling device disposed directly downstream of the drier and the cooling rollers accommodated therein. In this way, the length of the web path between the last cooling roller in the web cooling device and the machine unit disposed downstream of the web cooling device changes which causes a change in the web tension. The above-described web cooling device has no kind of features which could be used to prevent or at least to reduce a change in the web tension brought about by a movement of the web cooling device.

SUMMARY OF THE INVENTION

[0005] It is accordingly an object of the invention to provide a paired roller configuration which overcomes the above-mentioned disadvantages of the prior art devices of this general type.

[0006] With the foregoing and other objects in view there is provided, in accordance with the invention, a paired roller configuration. The paired roller configuration includes a first machine unit, a second machine unit, a first roller disposed rotatably in the first machine unit, and a second roller disposed rotatably in the second machine unit and substantially parallel to the first roller. The first and second rollers guide a web that wraps partly around the first and second rollers. The first roller is disposed such that the first roller can move in the first machine unit. At least one connecting unit couples the first roller to the second roller in such a way that in a event of one of a movement and a deformation of the first machine unit, the first roller and the second roller remain disposed substantially parallel to each other and at a substantially constant spacing.

[0007] The configuration according to the invention of the first and the second roller advantageously prevents a movement and/or a deformation of the first machine unit leading to a change in web tension on the web path between the first and the second machine unit, and therefore ensures that the movement and/or deformation of the first machine unit has no negative effects on the transport and/or the processing of the web. According to the invention, the first and the second roller are coupled via the connecting unit, so that the parallelism and the spacing between the two rollers is substantially maintained, irrespective of a movement and/or a deformation of the first machine unit. For this purpose, according to the invention the first roller is disposed such that it can move in the first machine unit, which advantageously leads to the first roller executing a compensatory movement or relative movement to the movement and/or the deformation of the first machine unit, the compensatory movement being effected by the connector unit between the first and the second roller, which is disposed in the second machine unit, which is not moved and/or deformed.

[0008] The movement of the first machine unit can in this case be caused by thermal expansion or deformation of the first machine unit or else by other disruptive influences, such as vibration-induced movements.

[0009] Provision can advantageously be made for the machine that contains the first and second machine units to be provided with a device that contains at least the first roller, the second roller and the connecting unit.

[0010] Furthermore, the first roller in the first machine unit can advantageously be disposed such that it can move in such a way that a substantially horizontal movement of the first roller is made possible. By this, a horizontal movement and/or deformation of the first machine unit can advantageously be compensated for.

[0011] Furthermore, provision can be made for bearing units of the first roller each to contain at least one rolling element or one sliding element, which are mounted such that they can roll or slide on a respective rolling surface or sliding surface in or on a side wall of the first machine unit, that is to say form a loose bearing. Provision can be made in this case for the first roller to have, at both ends in each case, a bearing journal which is rotatably mounted in a bearing unit or bearing cage associated with a respective side wall of the first machine unit, so that the roller can be rotated on account of frictional forces or by a drive as it guides the web. The movement of the first roller, which opposes the movement and/or deformation of the first machine unit and can be understood as a compensatory movement, is advantageously made possible by the rolling elements or sliding elements associated with the bearing units and the respective rolling surfaces or sliding surfaces cooperating with these. For example, provision can be made for a respective side wall of the first machine unit to have an opening which is provided with a rolling surface or sliding surface, on which the bearing unit is mounted such that it can roll or slide by use of at least one rolling element or one sliding element. Furthermore, it is possible to dispose the rolling surfaces or sliding surfaces on an inner wall of a side wall of the first machine unit.

[0012] A further embodiment of the invention can be distinguished by the fact that the first roller is disposed in the first machine unit in such a way that the web is fed to the first roller in a direction which runs substantially perpendicular to a direction of the first machine unit in which a movement or deformation of the machine unit takes place. Feeding the web substantially perpendicular to the first roller advantageously leads to the change in the length of the web path, brought about by a compensatory movement of the first roller, being kept as low as possible in the feed section to the first roller. Furthermore, provision can also be made to dispose the first roller in the first machine unit in such a way that the web wraps around the first roller with a wrap angle between 45-135°, preferably 90°. The advantageous configuration of the first roller likewise leads to the direction of movement of the first machine unit and the feed direction of the web to the first roller being substantially perpendicular to each other, so that the magnitude of the displacement of the first machine unit does not lead to an identical magnitude of a length change in the web path.

[0013] Furthermore, provision can be made to dispose the first machine unit in the web running direction upstream of the second machine unit or downstream of the second machine unit. By appropriate selection of the configuration of the two machine units, it is advantageously possible for a movement and/or a deformation of the first machine unit to be compensated for by the paired roller configuration, irrespective of the sequence in which the first and the second machine unit are disposed in the web running direction.

[0014] In a further embodiment of the paired roller configuration according to the invention, the first roller can be the last cooling roller in the web running direction of a cooling roller group or a cooling roller stand. It is advantageously possible for the problem of the change in web tension during movement or deformation of a cooling roller group or cooling roller stand to be eliminated in a simple way, without the use of an additional roller and while saving costs and material.

[0015] Furthermore, it is possible for the second roller to be the first roller in the web running direction of a folder or a feed unit disposed upstream of a folder in the web running direction. The selection of the first roller of a folder or of a feed unit disposed upstream of a folder in the web running direction as the second roller of the paired roller configuration according to the invention likewise advantageously leads to it being possible to dispense with further rollers for preventing tension changes, saving costs and materials. Therefore, in a further embodiment of the paired roller configuration according to the invention, it is conceivable for the web to be fed directly from a last cooling roller of a cooling roller group or a cooling roller stand to the first roller of a folder or a feed unit disposed upstream of a folder in the web running direction, the two rollers constituting the first and the second roller of the paired roller configuration according to the invention.

[0016] The first and the second roller of the paired roller configuration according to the invention can, however, also be constructed as guide rollers, which can be disposed in the respective machine units with low costs and in a space-saving manner.

[0017] Furthermore, however, in a development of the idea of the invention, it is also possible for the paired roller configuration to have, instead of the second roller, a cylindrical web guide element, can be or is acted on which in particular by blown air. It is therefore possible, for example, for the configuration or device according to the invention to be implemented with a first roller and a web guide element as well, it being possible for the web guide element to be disposed to be rotationally fixed, for example. For example, a web guide bar or web turner bar to which blown air is applied can be used as a web guide element.

[0018] The paired roller configuration according to the invention can also be distinguished by the fact that the first roller is a cooling roller through which coolants flow and which is rotatably mounted and which is displaceably mounted, via bearing units containing supporting rollers, in recesses in the side walls of a cooling roller stand belonging to a web-fed rotary printing machine. The connecting unit has rods or couplers whose length can be adjusted separately and which in each case are attached by one end to a bearing unit of the cooling roller and by the other end to the second machine unit. In addition, further rods or couplers whose length can be adjusted separately are provided, which are in each case attached by one end to a bearing unit of the cooling roller and by the other end to the first machine unit. Such a paired roller configuration is distinguished by a simple and cost-effective construction, but implements the mobility of the first roller, on which the idea of the invention is based, relative to the first machine unit with high precision, with quick reaction and with permanent reliability. As a result of the adjustable-length rods or couplers, which are contained by the paired roller configuration according to the invention or by the device according to the invention, it is made possible in an extremely simple way for the printer to adjust the parallelism and the spacing of the first and second rollers, in particular to adjust them finely.

[0019] Although the last-named embodiment of the invention solves the problem in a simple way with mechanical devices, it is also possible, in a further embodiment, to provide a paired roller configuration or a device that, by use of precise signal transmitters, receivers and an evaluation unit, likewise provides the problem solution according to the invention. For example, provision can be made for the connecting unit which couples the first roller to the second roller or to the second machine unit to contain transmitters disposed on the first machine unit, in particular infrared, microwave or ultrasound transmitters, and receivers which are disposed on the second machine unit and assigned to the respective transmitters. Furthermore, at least one drive unit for displacing the movably disposed first roller is provided, and a control unit is provided which is connected to the transmitters, the receivers and the drive unit via data transmission lines. In this case, the respective transmitters can output pulses, which are picked up by the associated receivers and passed on to the control unit which subsequently calculates the propagation time of the pulses from the transmitter to the receiver and, via a change in the propagation time, calculates the change in spacing between the first and the second machine unit and transmits control signals to the drive unit, which effects a compensatory movement of the first roller in the first machine unit.

[0020] A web-processing machine, in particular a web-fed rotary printing machine, which has at least a first and a second machine unit, is distinguished by a paired roller configuration according to the invention.

[0021] In this-case, the first machine unit can contain at least one heating and/or cooling element, which moves and/or deforms the first machine unit as a result of material expansion on account of a change in temperature. By the paired roller configuration according to the invention or a device according to the invention which contains the paired roller configuration, the movement and/or deformation of the first machine unit, effected on account of the temperature change, can be corrected and, as a result, a change in web tension can advantageously be prevented.

[0022] A web-processing machine which contains a paired roller configuration according to the invention can further be distinguished by the fact that the first machine unit of the machine is a cooling roller stand, in particular a cooling roller stand disposed directly downstream of a web drier, firmly connected to the web drier or integrated into a web drier. In this way, movements, displacements and/or deformations of the cooling roller stand itself or movements, displacements and/or deformation imparted to the cooling roller stand by the web drier can advantageously be compensated for, by which a change in tension in the web is prevented or at least reduced.

[0023] Furthermore, it is also possible for the second machine unit of the web processing machine to be a folder or a feed unit disposed upstream of a folder in the web running direction. In this case, it is advantageously possible to correct disadvantageous movements or deformations of the cooling roller stand or of the drier by the paired roller configuration according to the invention, so that the web running into the folder and to be folded advantageously has a desired web tension, which is necessary for the precise and proper folding of the web.

[0024] Other features which are considered as characteristic for the invention are set forth in the appended claims.

[0025] Although the invention is illustrated and described herein as embodied in a paired roller configuration it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

[0026] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1a is a diagrammatic, side-elevational view of a paired roller configuration according to the prior art;

[0028]FIG. 1b is a plan view of the paired roller configuration according to the prior art before a movement of a first machine unit;

[0029]FIG. 1c is plan view of the paired roller configuration according to the prior art after the movement of the first machine unit;

[0030]FIG. 2a is a side-elevational view of the paired roller configuration according to the invention;

[0031]FIG. 2b is a plan view of the paired roller configuration according to the invention before the movement of the first machine unit;

[0032]FIG. 2c is a plan view of the paired roller configuration according to the invention after the movement of the first machine unit;

[0033]FIG. 3 is a perspective view of the paired roller configuration according to the invention; and

[0034]FIG. 4 is a plan view of the paired roller configuration according to the invention having transmitters and receivers.

Description of the Preferred Embodiments

[0035] In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case. Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1a thereof, there is shown a paired roller configuration 1 according to the prior art, which contains a first roller 2 in a first machine unit 3 and a second roller 4 in a second machine unit 5. A web 6 is led over an upstream roller 7 and then over the first roller 2 and the second roller 4. The rollers 7, 2 and 4 are rotatably mounted in side walls 12-15 of the machine units 3 and 5, as can be seen for example from FIG. 1b. There, the first roller 2 and the second roller 4 are shown in a plan view of the paired roller configuration according to the prior art, the rollers 2 and 4 being rotatably mounted in the side walls 12, 13, 14 and 15 of the first and the second machine unit 3, 5 by bearings 8, 9, 10 and 11. As can further be seen from FIG. 1c, a movement of the side wall 12 of the first machine unit 3, which for example can be brought about by a deformation of the machine unit 3, leads to pivoting of the first roller 2, as a result of which the parallelism between the first roller 2 and the second roller 4 is disrupted. The displacement of the side wall 10 of the first machine unit 3 is indicated by a dashed line 16, which represents the position of the side wall 12 of the first machine unit 3 before the displacement. A comparison of Figs. 1b and 1 c, which show both paired roller configurations according to the prior art, makes it clear that the displacement of at least one side wall of the first machine unit 3 must lead to a change in web tension in the web 6. In this case, the web tension may decrease, if the first roller 2 comes closer to the second roller 4, but can also increase if the first roller 2 moves away from the second roller 4. In addition, FIG. 1c reveals that the deformation of the first machine unit 3 leads to a variation in the web tension running transversely with respect to the web running direction.

[0036]FIGS. 2a, 2 b and 2 c show the paired roller configuration according to the invention, the first roller 2 is disposed in the first machine unit 3 and the second roller 4 is disposed in the second machine unit 5. The web 6 is led over the upstream roller 7, over the first roller 2 and over the second roller 4. The first roller 2 is rotatably mounted in a bearing unit 18 by a bearing journal 17. In addition, the bearing unit 18 is firmly connected to the second machine unit 5 by a rod 19 and has loose bearing with rollers 20, 21, which are mounted such that they can roll on a rolling surface 23 in the side wall of the first machine unit 3.

[0037] The plan view of the paired roller configuration according to the invention in FIG. 2b shows the first and the second machine unit 3, 5 before any deformation of the first machine unit 3. Comparison of FIG. 2b with FIG. 2c, in which a plan view of the paired roller configuration according to the invention is likewise shown, reveals that in the event of displacement of the side wall 12 of the first machine unit 3, the parallelism and the spacing of the first roller 2 from the second roller 4 is maintained, as a result of which the web path of the web 6 between the first machine unit 3 and the second machine unit 5 also remains unchanged, so that no change in web tension occurs in the web path between the first roller 2 and the second roller 4. In this case, the deformation or the expansion of the side wall 12 is represented by a dashed line 16, which shows the position of the side wall 12 before the deformation. As further revealed by a comparison of FIG. 2a and FIG. 2c, displacement of the first machine unit 3 likewise leads to displacement of the upstream roller 7, which is not shown in FIG. 2c, for clarity, but a displacement of the upstream roller 7 has only a slight influence on the web path length between the upstream roller 7 and the first roller 2, since this section of the web path is oriented substantially perpendicular to the direction of movement of the first machine unit 3 or a side wall of the first machine unit 3.

[0038]FIG. 3 shows a perspective view of the paired roller configuration according to the invention, which can also be understood as a device for preventing tension changes, the device contains the first roller 2, the second roller 4, adjustable-length connecting rods 24 and 25 and adjustable-length connecting rods 26 and 27. The first roller 2, which in this case is the last cooling roller in the web running direction of the first machine unit 3 functioning as a cooling roller stand 3, is rotatably mounted in the respective bearing units 18 by its bearing journals 17, the bearing units 18 each having the roller 20, which is mounted such that it can roll on a guide 28, for example a rolling surface in or on the frame 13 of the cooling roller stand 3. The adjustable-length rods 24 and 25 are attached by their one end in each case to the bearing units 18 and by their other ends in each case to the side wall or frame 14 or 15 of the second machine unit 5. By the adjustable-length rods 24 and 25, according to the invention the parallel alignment of the two rollers 2 and 4 and their spacing is maintained even in the event of a movement, displacement or deformation of the first machine unit 3, since the first roller 2 is forced, by the coupling to the machine unit 5 imparted by the variable-length rods 24 and 25, to make a compensatory movement relative to the first machine unit 3. In this case, the compensatory movement takes place in the horizontal direction as a result of the rollers 20 rolling on the rolling surface 28. By the adjustable-length rods 26 and 27 that are likewise provided, it is substantially possible to prevent the first roller 2 executing a movement with a vertical component. The adjustability of the lengths of the rods 24, 25, 26 and 27 advantageously makes fine adjustment possible during the alignment of the first roller 2. An arrow 29 in FIG. 3 represents the web running direction, but it can be seen by those skilled in the art that the device according to the invention also functions in a manner according to the invention in the event of a reversed web running direction.

[0039] Furthermore, FIG. 4 shows a schematic plan view of the roller configuration according to the invention, again the first roller 2 is disposed in the first machine unit 3 and the second roller 4 is disposed in the second machine unit 5. On its side walls 12 and 13, the first machine unit 3 has transmitters 30 and 31, which interact with respective receivers 32 and 33 on the side walls 14 and 15 of the second machine unit 5. In addition, the paired roller configuration according to the invention has a control unit 34, which is connected via lines 35, 36, 37 and 38 to the transmitters 30 and 31 and the receivers 32 and 33. Furthermore, the device according to the invention contains drive units 39 and 40, which are connected to the control unit 34 via lines 41 and 42 and effect a movement of the first roller 2 when activated by the control unit 34. The control unit 34 transmits control signals to the transmitters 30 and 31 via the lines 35 and 38, the transmitters being caused by the control signals to emit signal pulses, for example infrared, microwave or ultrasound pulses, which are consequently received by the receivers 32 and 33 and, in the form of control signals, are passed on via the lines 36 and 37 to the control unit 34. The control device 34 calculates the propagation time of the pulses transmitted by the transmitters 30 and 31 between the side walls 12 and 13 of the first machine unit 3 and the side walls 14 and 15 of the second machine unit 5, for example from the time at which the control signals are sent out via the lines 35 and 36 and the time at which the control signals arrive via the lines 37 and 38. In the event of a movement, deformation or displacement of one of the side walls 12 or 13, as represented for example by the dashed line 16 in FIG. 4, the propagation time of the signal from the transmitter 30 to the receiver 32 is shortened, from which the control device 34 can in turn calculate the magnitude of the movement, deformation or displacement. In this case, the relationship Δs=cΔt applies, Δs being the change in spacing between the side walls, c the speed of the waves transmitted, for example the speed of light or sound, and Δt the propagation time of the transmitted signal. In order to compensate for the magnitude, control signals are led via the lines 41 and 42 to the drive units 39 and 40, which cause the bearing units 18, together with the first roller 2, to make a corresponding compensatory movement. In this case, the drive units 39 and 40 may contain, for example, conventional positioning devices containing motors or else linear drives. 

I claim:
 1. A paired roller configuration, comprising: a first machine unit; a second machine unit; a first roller disposed rotatably in said first machine unit; a second roller disposed rotatably in said second machine unit and substantially parallel to said first roller, said first and second rollers guiding a web which wraps partly around said first and second rollers, said first roller disposed such that said first roller can move in said first machine unit; and at least one connecting unit coupling said first roller to said second roller in such a way that in a event of one of a movement and a deformation of said first machine unit, said first roller and said second roller remain disposed substantially parallel to each other and at a substantially constant spacing.
 2. The paired roller configuration according to claim 1, wherein: said first machine unit has a side wall with a surface selected from the group consisting of a rolling surface and a sliding surface; and said first roller has bearing units, said bearing units each containing at least one element selected from the group consisting of a rolling element and a sliding element, mounted such that said element can roll or slide on said surface of said side wall of said first machine unit.
 3. The paired roller configuration according to claim 1, wherein said first roller in said first machine unit is disposed such that the web is fed to said first roller in a direction running substantially perpendicular to a direction of said first machine unit, the direction of said first machine unit defined as a given direction of movement or deformation of said first machine unit.
 4. The paired roller configuration according to claim 1, wherein said first roller in said first machine unit is disposed such that the web wraps around said first roller with a wrap angle in an angular range between 45° and 135°.
 5. The paired roller configuration according to claim 1, wherein said first roller in said first machine unit is disposed such that said first roller can move substantially horizontally.
 6. The paired roller configuration according to claim 1, wherein said first machine unit is disposed upstream of said second machine unit in a web running direction.
 7. The paired roller configuration according to claim 1, wherein said first roller is a last cooling roller in a web running direction of a cooling roller group.
 8. The paired roller configuration according to claim 1, wherein said second roller is a first roller in a web running direction of a folder.
 9. The paired roller configuration according to claim 1, wherein said second roller is a cylindrical web guide element acted on by blown air.
 10. The paired roller configuration according to claim 1, wherein said first machine unit has side walls with recesses formed therein, said first machine unit functioning as a cooling roller stand for a web-fed rotary printing machine; wherein said first roller has bearing units and is a cooling roller through which coolant flows and said first roller is rotatably mounted and displaceably mounted, by said bearing units, said bearing units having supporting rollers disposed in said recesses in said side walls; wherein said connecting unit has rods with a given length that can be adjusted separately and are in each case attached by a first end to one of said bearing units of said cooling roller and by a second end to said second machine unit; and said connecting unit has further rods with a length that can be adjusted separately and are in each case attached by a first end to one of said bearing units of said cooling roller and by a second end to said first machine unit.
 11. The paired roller configuration according to claim 1, wherein connecting unit has transmitters disposed on said first machine unit and receivers disposed on said second machine unit and each of said transmitter is associated with a respective one of said receivers; including at least one drive unit for displacing said first roller; data transmission lines; and including a control unit connected to said transmitters, said receivers and said drive unit through said data transmission lines.
 12. The paired roller configuration according to claim 4, wherein said wrap angle is substantially 90°.
 13. The paired roller configuration according to claim 1, wherein said first machine unit is disposed downstream of said second machine unit in a web running direction.
 14. The paired roller configuration according to claim 1, wherein said second roller is an initial roller in a web running direction of a feed unit disposed upstream of a folder in the web running direction.
 15. The paired roller configuration according to claim 11, wherein said transmitters are selected from the group consisting of infrared transmitters, microwave transmitters and ultrasound transmitters.
 16. A web-processing machine, comprising: a first machine unit; a second machine unit; a first roller disposed rotatably in said first machine unit; a second roller disposed rotatably in said second machine unit and substantially parallel to said first roller, said first and second rollers guiding a web which wraps partly around said first and second rollers, said first roller disposed such that said first roller can move in said first machine unit; and at least one connecting unit coupling said first roller to said second roller in such a way that in a event of one of a movement and a deformation of said first machine unit, said first roller and said second roller remain disposed substantially parallel to each other and at a substantially constant spacing.
 17. The web-processing machine according to claim 16, wherein said first machine unit contains at least one element selected from the group consisting of heating elements and cooling elements, said element able to move and deform said first machine unit as a result of material expansion on account of a change in temperature.
 18. The web-processing machine according to claim 16, wherein said first machine unit is a cooling roller stand.
 19. The web-processing machine according to claim 16, wherein said second machine unit is a folder.
 20. The web-processing machine according to claim 16, wherein said second machine unit is a feed unit disposed upstream of a folder in a web running direction.
 21. The web-processing machine according to claim 16, wherein said first machine unit is a cooling roller stand disposed one of directly downstream of a web drier, firmly connected to said web drier, and integrated into the web drier.
 22. A web-fed rotary printing machine, comprising: a first machine unit; a second machine unit; a first roller disposed rotatably in said first machine unit; a second roller disposed rotatably in said second machine unit and substantially parallel to said first roller, said first and second rollers guiding a web which wraps partly around said first and second rollers, said first roller disposed such that said first roller can move in said first machine unit; and at least one connecting unit coupling said first roller to said second roller in such a way that in a event of one of a movement and a deformation of said first machine unit, said first roller and said second roller remain disposed substantially parallel to each other and at a substantially constant spacing. 